1. Field of the Invention
The present invention relates in general to a leaf spring assembly used for mounting a vehicle axle to a vehicle frame and in particular to a pad or separator loosely positioned between the end of the leaf spring assembly and a spring hanger to improve wear and ride characteristics and a method for installing the pad.
2. Description of the Prior Art
Laminated leaf spring assemblies for mounting vehicle axles to the vehicle frame are well known in the art. The conventional leaf spring assembly used in vehicles of various types is ordinarily securely attached at each leaf spring end to a spring hanger attached to the vehicle frame. The spring assembly forms a sliding fit with the spring hanger at one or both ends of the spring assembly. The spring assembly must be permitted to change shape and length as the load on the spring assembly changes. As the load on the leaf spring changes and the end or ends of the leaf spring slides through the spring hangers, the end surfaces of the leaf spring rub against the surface of the spring hangers resulting in repeated wear and tear of the contacting surfaces of the leaf spring and/or the spring hangers. Additional wear and tear results between the individual leaf spring members. Pads or separators have been used between the individual leaf spring members and between the leaf spring ends and the spring hangers.
With respect to pads or separators positioned between individual leaf spring members of the laminated leaf spring assembly, reference may be had to U.S. Pat. Nos. 2,801,100; 3,159,389; 3,195,876; 4,750,718; 3,305,231; and 2,649,296. The separator pads or layers between the respective leaf spring members in the noted patents are made from a variety of different materials including polyethylene, rubber, polyester elastomers, Delrin and Nylon. These pads extend along the lengths of the respective leaf spring members but are not positioned at the ends of the leaf spring assembly.
With respect to pads between the end of the leaf spring assembly and the spring hanger, reference may be had to U.S. Pat. No. 2,983,504 to Reuter and U.S. Pat. Nos. Re 23,252 and 2,577,322 to Frazier. The pad in the Reuter patent is made from polyester reinforced with an embedded metal plate. The Reuter pad is rigidly bolted to the spring hanger and would thus have to be installed either as original equipment or after the spring assembly has been completely removed from its mounting. The Frazier patents disclose wear plates of rubber or similar material bolted to the spring hanger. Thus, the wear plates in the Frazier patent are rigidly mounted and must be installed either as original equipment or with the spring assembly completely removed from the spring hanger. If not installed as original equipment, the installation of the prior art pads between the end of the leaf spring assembly and the spring hanger is labor intensive and costly. If the installation is too labor intensive and costly, the operator may decide that the pads are not necessary or cost effective.
Accordingly, there exists a need for a pad or separator which can be quickly, easily, and cheaply installed on existing vehicles without the necessity of removing the spring assembly from the spring hanger and without being rigidly attached to the spring hanger. Furthermore, the pad should lubricate the end of the spring assembly to minimize squeaking and wear.